Mark Coles profiles Sanjeev Gupta who this week met the Business Secretary Sajid Javid to discuss a possible deal to buy Britain's biggest steelworks at Port Talbot. In recent months he's invested significantly in British steel but before all that, in his earlier life, Gupta also bought and sold bicycles, sugar - even frozen chicken feet and fish heads. We ask his wife Nicola, sister Angeli and colleague Douglas Dawson what makes this entrepreneur tick - and why he thinks he can succeed in Port Talbot where previous owners have failed.Producer: Smita Patel.

Mark Coles profiles the actress, Sophie Okonedo, star of the new Sunday night drama, Undercover. She plays a successful barrister who discovers her life is based on a series of lies.Okonedo has a career encompassing stage, screeen and television, with parts as diverse as a future Queen Elizabeth (Liz Ten) in Doctor Who, to playing Winne Mandela. She was nominated for an Oscar for her role in Hotel Rwanda.Director Dominic Cooke, fellow actor Adjoa Andoh and writer Peter Moffat tell us why they describe Okonedo as a trailblazer.Producers: Smita Patel and Phoebe Keane.

n 2002 the British journalist Nick Denton created Gawker in the US, a website which made its name breaking news and celebrity gossip.Last week a US court ordered the site to pay Hulk Hogan $140 million in damages, after Gawker ran a clip from a sex tape involving the wrestling star.Mark Coles profiles the man friends describe as being "ahead of his time" and a "visionary".But Mark also discovers how, as a journalist, Nick Denton reveals other people's secrets, while carefully guarding his own.Producers: Katie Inman and David Rhodes.

"Ambitious", "cold-hearted" and "calculating"; just some of the words used to describe Frauke Petry, leader of Germany's Alternative fur Deutschland (AfD) party. She has suggested German border police should be allowed to use firearms to deter illegal immigrants.The populist, right-wing AfD has, under her controversial leadership, jumped from winning just a few percent of the vote at the 2013 federal elections, to more than 20 percent in some parts of Germany in last weekend's regional elections. The results surprised many. But is her brand of politics sincere, or - as some say - pure opportunism? And how far could she take the AfD? Ed Stourton finds out.Producer: Wesley Stephenson.

Senator Ted Cruz is a hardliner, even by the standards of his native Texas: anti-abortion, anti-gay marriage, in favour of the death penalty and fiercely opposed to gun control. But in the race to be the next US president, some believe he has the best chance of beating Donald Trump to the Republican nomination. Son of a Cuban immigrant - and a virtual unknown three years ago - the 'anyone-but-Trump' candidate's ascent through Republican ranks has been as stratospheric as his style is divisive. With the 2016 American election looming, we profile a man who, as a teenager, used to tour the Deep South reciting the US Constitution by heart. Making his name as a hot shot young lawyer, Senator Cruz helped George W. Bush reach the White House by winning a court battle over the infamous Florida election recount. And as a rookie politician, he made headlines with a marathon 21-hour filibuster featuring children's stories by Dr Seuss.We hear from early backers and political opponents, those who shared Ted Cruz's school days and witnessed his early legal triumphs. With make-or-break Republican primaries coming thick and fast - and Super Tuesday having transformed the competition - how has a politician with almost as many enemies on his own side as among the Democrats come within sight of the White House? What impact has his Christian faith had on his politics? And can Senator Cruz become - as he dreamed as a teenager - the most powerful man in the world?

For more than 30 years Jenny Beavan has been designing beautiful and historically accurate costumes, for film and stage. But though she cares intensely how the costumes look on the actors and on screen, she has little interest in fashion or dressing up herself. So despite being called a bag lady at the Baftas she went along to collect her second Oscar in comfortable clothes.Presenter - Becky Milligan Producer- Shabnam Grewal and Elizabeth Cassin.

Chris Bowlby profiles the German art historian and curator Dr Hartwig Fischer, who this year takes over one of the most important jobs in UK culture: director of the British Museum. What can the museum's visitors - and its staff - expect from the new man in charge?Producer: Smita Patel.

Millions will miss Lady Violet's withering one-liners now that Downton Abbey is over. Chris Bowlby profiles one of Britain's most successful actors: Maggie Smith. Her extraordinary career has spanned Shakespeare on stage, Hollywood films and, of course, popular televison drama.Producer: Smita PatelPhoto credit: "Downton Abbey" / Carnival Films.

Elon Musk, the billionaire owner of SpaceX and Tesla Motors, has a plan to stop computers from taking over the world. The co-founder of Paypal - who made his first fortune in his twenties - has joined other tech giants to fund a not-for-profit company called OpenAI. Its aim is to develop the most advanced forms of artificial intelligence and then to share the results. Musk is among a group of thinkers - including Stephen Hawking - who have warned that AI could eventually lead to the end of the human race. His idea is that by making AI 'open source', powerful corporate interests will be kept in check. Mark Coles explores the life of a man with a passion for rockets, cars and a plan to retire to Mars.Producers: Smita Patel and Sally Abrahams.

Mark Clarke was once a rising star in the Conservative Party. He was a prominent figure who started and led 'RoadTrip2015', a project to bus young Conservatives into marginal seats to campaign door-to-door. Clarke was dubbed the 'Tatler Tory' after the magazine tipped him as a future minister. But he was recently expelled from the party following lurid allegations of blackmail and bullying, and the tragic suicide of one fellow activist.Presenter: Mark Coles Producer: Sonia Rothwell.